<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        let form
        form = {
            a: 1,
            b: 4,
            c: 3
        }
        form = {
            a: 1,
            b: 2,
        }
        //a:1,b:2,b:4,c:3
        // a: 1, b: 4
        console.log(form)
    </script>
</body>

</html>